Lined Pipe Pressure Loss Diagram

Pressure drop diagrams for PTFE, PP, PFA and PVDF-lined pipes

The diagrams below indicates the pressure loss with water flow in PTFE-lined steel pipes schedule 40.

The pressure drop calculations are made with the D'Arcy-Weisbach Equation.

• Fluid : Water
• Pipe : PTFE-lined Steel Pipes - Schedule 40
• Temperature : 20.0 ^oC (68.0 ^oF)
• Density : 998.3 kg/m³ (62.0 lb/ft³)
• Kinematic Viscosity : 1.004E-6 m²/s (0.01 stokes) (1.08E-5 ft²/s)
• Pipe Roughness Coefficient : 3.0E-6 m

Pressure Drop - Imperial Units

• 1 gal (US)/min =6.30888x10^-5 m³/s = 0.0227 m³/h = 0.06309 dm³(litre)/s = 2.228x10^-3 ft³/s = 0.1337 ft³/min
• 1 ft/s = 0.3048 m/s
• 1 psi (lb/in²) = 6,894.8 Pa (N/m²) = 6.895x10^-3 N/mm² = 6.895x10^-2 bar = 27.71 in H₂O at 62^oF (16.7^oC) = 703.1 mm H₂O at 62^oF (16.7^oC) = 2.0416 in mercury at 62^oF (16.7^oC) = 51.8 mm mercury at 62^oF (16.7^oC) = 703.6 kg/m² = 2.307 Ft. H₂O

Pressure Drop - SI units

• 1 Pa = 10^-6 N/mm² = 10^-5 bar = 0.1020 kp/m² = 1.02x10^-4 m H₂O = 9.869x10^-6 atm = 1.45x10^-4 psi (lbf/in²)
• 1 liter/s = 10^-3 m³/s = 3.6 m³/h = 0.03532 ft³/s = 2.1189 ft³/min (cfm) = 13.200 Imp.gal (UK)/min = 15.852 gal (US)/min = 792 Imp. gal (UK)/h
• 1 m/s = 3.6 km/h = 196.85 ft/min = 2.237 mph

The diagram above is based on the inside thickness of schedule 40 steel pipes with PTFE as the lining material. Common thickness of other lining materials are indicated in the table below.

• PTFE - PolyTetraFluoroEthylene
• PP - PolyPropylene
• PFA - Perfluoroalkoxy Fluorocarbon
• PVDF - Polyvinylidene Fluoride

^*) used in the diagrams above

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